Weapon for a demoknight? Either the Eyelander or the Persian Persuader. Eyelander is always fun and still is viable if you use a grenade launcher. The Persuader makes it impossible to get more grenades, and the boots you can use instead aren't even as useful, but at least the Persuader lets you charge twice as often.

It looks great, it looks AWESOME, but its stats aren't actually good compared to what else you can use. It can be fun if you're a demoknight freak that uses the controller exploit like LeiLei, but aside from that, there's no real point to it.

Persian Persuader all the way, I usually play that weapon. But also, I like the Scotsman Skullcutter for its damage, Goes great if you time it with the critical boost and ram with Splendid Screen.

But with the damage from the Splendid Screen bash, plus the guaranteed melee crit after the bash (which you can't even know if it's a glitch or not >_>), you don't even need the extra damage from the Skullcutter, the frying pan would kill just as well.

The Skullcutter is cool in that it has the extended melee range and is one of the few weapons he has that keeps random crits, and the demoknight could make good use of that extra damage on a melee weapon (unlike the Sniper with the Shahanshah which can't benefit as much) but the speed debuff just hurts. You now walk at 78% speed, while Heavies walk at 77%. It gets harder to even hit the guys in the first place, even your charges don't go as far. It's even more annoying because this is always in effect, not just when you have the weapon out, and you can clearly notice that you're slower, just because you're carrying that darn thing.

Anyways, best Demo sword IMO is Persian Persuader.Hp from ammo and a fast charge recharge are two priceless abilities with the low cost of being unable to pick up ammo for a melee-only subclass (In other words, no downside).